This invention relates to wiring terminals for electrical apparatus. More particularly, the invention relates to electric switches wherein the housing is extended to substantially enclose the wiring terminals.
Electric switches used to control apparatus which operates in a high dust environment require particular sealing structures to prevent the contacts from becoming contaminated or fouled by the dust. A general reduction in size of hand held tools such as electric sanders has reduced the size available for the electric switch for controlling the sander, thereby requiring a similar reduction in size of the switch. As a result of such size reduction, the space provided between wiring terminals is commonly at a minimum distance acceptable to the various certifying agencies. When used in a hand sander or similar device, dust penetrating the housing of the sander can build up in the wire termination area of the switch, establishing an electrical bridge across the terminals and creating a potential hazard for the apparatus. Another problem encountered with electrical switch wiring terminals when the switch is used on apparatus subject to vibratory motion is that the screws tend to loosen and occasionally fall out of the terminal hole before the electrical connection is actually broken, and the screw is then very susceptible to being permanently lost.
This invention provides a switch which is well suited for miniaturization wherein the housing is provided with a separate chamber for the wiring terminals, such chamber being sealed off from the switch contact chamber and essentially sealed off from the exterior of the housing. Each terminal assembly is provided with an individual substantially sealed cavity within the housing to isolate it from adjacent terminal assemblies. The housing is provided with openings for inserting wire conductors to the terminal assemblies and access openings for the screws of the terminal assemblies, and further serves to form a simple structure for captivating or retaining the screw within the housing, and where so desired, assembled to the terminal.